In Sims 2 I made a boring, elderly couple named John and Jane doe. I built them a normal house, like any other, but in the back / hidden room resided a dungeon. They would lure sims to their house for cake and tea only to trap them in a cell in the dungeon. Sims generally died there in a stone room with only a window to the outside world, but nobody ever heard their cries. They generally died in puddles of their piss and vomit from the spoiled food I fed them.
It was probably the only time in gaming I've ever stopped, considered what i was doing, and stopped. It was just too evil.